One person was stabbed to death and two others wounded after they were attacked by a man in the centre of the Australian city of Melbourne on Friday, police said.

A video shared on Twitter clearly showed the attacker, a dark-skinned middle-aged man wearing a black sweatshirt, viciously swinging the knife he used to stab the civilians at police officers at the scene. The video also shows another individual, dubbed ‘trolley man’, quickly barging in with a trolley directly hitting the attacker and stalling him to buy the police some time.

Police later shot the man who threatened officers with a knife and he is in a critical condition under guard at a hospital, Victoria Police Superintendent David Clayton told reporters.

“Three people have been stabbed, unfortunately one of them is deceased at the scene,” he said. “There is no known links to terrorism at this stage we will keep an open mind as to whether there is any link.”

Local media showed footage of a large man slashing wildly at police officers before being shot.

Police warned people to avoid the area, although the suspect is believed to have been detained.